#include<iostream>
#include<vector>
using namespace std;

class Solution {
public:
    int singleNumber(vector<int>& nums) {
        int leng = nums.size();
        int ret = 0;
        for (int i = 0; i < leng; i++)
        {
            ret = ret ^ nums[i];
        }
        return ret;
    }
};

int main()
{


}